1. Field of the Invention
The present invention generally relates to an engine with an integrated continuously variable transmission (CVT) that extends between a crankshaft and a transmission shaft. More particularly, the present invention relates to such a combination in which rotation of the transmission shaft is provided to a drive shaft output.
2. Description of the Related Art
An engine having an integrated continuously variable transmission is shown and described in JP-A-2000-18348. In the configuration shown in FIG. 4 of the Japanese reference, one end of a crankshaft of the engine carries a drive pulley of the continuously variable transmission. The other end of the crankshaft carries a generator, such as a flywheel magneto. Between the generator and the drive pulley, the crankshaft comprising webs to which the pistons are connected with connecting rods. Between the generator and the web closest to the generator, the crankshaft comprises a gear. The gear is used to drive a balancer shaft. The balancer shaft carries a balancer weight that offsets the effects of the webs of the crankshaft during rotation of the crankshaft. The balancer shaft also drives through a geared coupling a coolant pump. A centrifugal clutch also is positioned in line with the crankshaft.
This arrangement advantageously reduces crankshaft vibration through the use of the balancer shaft; however, the centrifugal clutch must be located in a position along the crankshaft axis that will provide ample space for the balancer shaft. As a result, the engine size must be increased in the vicinity of the crankshaft in order to accommodate the balancer shaft and the centrifugal clutch.